Nonlinear Equations

CONTIN - systems of nonlinear equations.
GAUSS - matrix programming language.
HARWELL Library - linear and nonlinear programming, nonlinear equations, data fitting.
HOMPACK - nonlinear equations and polynomials.
LANCELOT - large-scale problems.
LOQO - Linear programming, unconstrained and constrained nonlinear optimization.
MINPACK-1 - nonlinear equations and least squares.
NITSOL - systems of nonlinear equations.
OPTIMA Library - optimization and sensitivity analysis.
PETSc - parallel solution of nonlinear equations and unconstrained minimization problems.